Platen shift-key for type-writing machines.



PATENTED FEB.18, 1908.

s. B. PRENTISS PLATEN SHIFT KEY FOR TYPE WRITING MACHINES.

APPLICATION FILED MAR. 10, 1904.

INVENTOR struction, with a shift key UNITED STATES PATENT OFFICE.

SPENCER B. lltEN'llSS, OF WASHINGTON, DISTRICT Oi COLUMBIA;

PLATEN SHIFT-KEY FOR TYPE-WRITING MACHINES.

Specification of Letters Patent.

Patented Feb. is, 1908.

Application file l March 10. 1904. Serial No. 197.525.

My invention relates to platen shift-keys for typewriting machines, and has for its object the production of a'device of this general character by means of which exponent numbers or lettersmay be readily produced in the writing without turning the platen for that purpose.

Various devices or'keys have heretofore been produced for of ty )ewritiug mac ines so that a character may be written above the line, and it is to this class of devices that my improvement belongs.

' in carrying my invention into effect I provide a typewriting machine, having a platen and laten shift lever, and which may be of, any nown or hereafter to bedevised conmounted upon or carried by the platen shift lever and operative when depressed to produce a partial shift of the platen, the construction and arrangement of the key being such as to permit the full movement of the shift lever and the full shift of the platen. are now constructed my improvement may be made as a permanent addition upon the lever of the shift key, or it may be separately manufactured as an attachment to be placed upon machines alreadv completed andin use.

'l he invention is illustrated in the accompanying drawings, in which lihure l is a conve of a cypcwriting machine equipped with my improvement; Fig. 12 is a side view of a shift key constructed according to my invention; Fig. 3 is a front view of the same showing in whole lines the position of the parts in their operated or depressed position, and in dotted lines their position taken when the platen is shifted fully; and Fig. 4 is a detached view in perspective of the device in its idle position during full shift of the platen.

Referring to the drawings, A is the frame of a typewriting machine, B the platen, and U C represent in end elevation the lovers of a platen shift mechanism moving together and provided with keys 0 c.

D is an extension for the which it may be secured shift lever (l to by any suitable artly shifting the platen As machines ntional representation means such as a collar (1 and set screw (1. Hinged at d to extension D, and capable of independent motion above its normal position 'only, and projectin over a stop such as a portion a of the machine. frame, is a key member (i having a contact piece (1 on its under surface.-- Key member (i is limited to this independent motion above its normal position, and has a rigid connection with cirtension D under operative pressure downward, by reason of the lip d which extends .under and engages the lower end of said extension D. The parts are so proportionedthat when collar (11 is properly adjusted the key member d," will be but a short distance above stop a, as shown in Fig. 2, and this distance may be varied according to the position above the line at which it is 'desired to place the exponent by merely adjusting the collar. Akey piece d inay be provided on key member (1 as shown in Fig. 3, sothat the pressure applied will always be over the he operation of the device is obvious: When it is desired to write a character with an exponent, such as a, 13*, let, the charac ter is struck in the usual way, then key memher (1 is pressed against stop a as shown in Fig. 3, and the exponent number-or letter then struck which will always appear the proper distance above the line. In ordinary writing when either of the regular shift keys 0 c are depressed to produce a full shift of the platen, the hinge d will permit the extension D to go downjthe required distance, key memner d restingidly on sto o, as shown in Fig. 4 and by dotted lines in big. 3.

It will be understood that many variations in fonm and changes in proportions of parts may be made without departing from the spirit of the invention, the form shown and described being merely illustrative, and such 1. In a typcwriting machine, the combination with a platen and a platen shift lever provided with a shift key, of a shift key membcr wholly mounted upon and carried by said lever for contact with a fixed portion of tion. with a platen and a platen shift lever, of

a fixed stop, a shift key member having a hinged. connection with said. lever for upward. motion with relation thereto and projecting over said fixed stop, the parts being so arran ed that when ressure is a )lied to the key'membor said step limits the platen shift, but when the shift lever is given its full movement said key member engages said stop and moves idly upon its hinge,

' 3. In a typ'ewriting machine, the combination with a platen and a platen shift lever, of fixed stop, a shift key memberadjustably mounted upon and having a hinged connection with said lever f or upward motion with relation thereto and projecting over said fixed stop, the parts being so arranged. that when pressure is applied to the key member said stop limits the platen shift, butwhen the shift lever is given its full movement said key member engages said stop and moves idly u on its hinge;

. 4. fir a typewriting machine, the combination with a platen and a platen shift lever, of a fixed. stop, a shift key member having a hinged connection with said lever, for upward motion with relation thereto and projecting over said fixed stop, and a key piece upon said key member directly over said stop, the parts being so arranged that when pressure is applied to said key piece said stop limits the platen shift a predetermined amount, but when the shift lever is given its full movement said key member engages said stopaand moves idly upon its hinge.

5a In a tvpewriting machine, the combination with said lever and. projecting over a fixed portion of the machine frame, whereby when the key member is depressed said frame forms a stop to limit the platen shift, but when the shift lever is given its full movement said key. member moves upon its hin e.

6 As an article of manufacture, an auxiliary shift key for typewriting machines comprising a body-portion provided with means for attachment tothe pl atenshiftlever, and a key member carrying a single key-piece and hinged to said body-portion for rigid relation therewith under pressure upon said keypiece but to move idly upon its hinge by engagementwitha fixed stop.

7. As an article of manufacture, an auxiliary shift key for typewriting machines comprising a body portion provided with means for attachment to the platen shift lever, and a key member hinged to said body portion to form a rigid connection therewith under 0 erative pressure but capable 'of movement upon the hinge in. the opposite direction.

8. As an article of manufacture, an auxiliary shift key for typewriting machines comprising a body portion provided with a split collar and an adjustment screw for attach- I ment to the platen shift lever, and a key member hinged to said body portion to form a rigid connection therewith under operative pressure but capable of movement upon the hinge in the opposite direction.

In testimony whereof 'I have signed my name to this specification in the presence of two subscribing Witnesses.

SPENCER B. PRENTISS. Witnesses:

ALEXANDER S. STEWART, ELIZABETH GRIFFITH. 

